1. Field of the Invention
The present invention relates to a multichannel phone plug, and more particularly, to a single phone plug which transmits five or six sound signals and has the multichannel function, or the like.
2. Description of the Prior Art
A so-called phone plug, shown in FIG. 1, is constructed as a shaftlike terminal (a) being pluggable into a phone jack of the analog signal output for an electric connection. The sound signals are transmitted through a sound signal cable to a speaker or the commercially available earphone. Thus, the phone plug (a) has the convenience in operation and in use regarding the connection of sound signals.
However, the commercially available phone plug (a) has only few electric poles and can only transmit at most two sound signals, that is, the left and right sound channels and the earth terminal, thereby forming a stereophonic effect. Consequently, the current headphones can only reach two channel sound effect.
With the improvement of the digital technology and the popularization of the digital audio-video products like DVD players or surround amplifiers, they basically own the Dolby Digital and DTS decoding functions through which the digital signals are decoded to output the analog signals to the speaker. Therefore, DVD players or the surround amplifiers include an analog output terminal of 5.1-ch sound signals for establishing a home theater system with TV, DVD player, surround amplifier and 5.1-ch speaker.
In order to reach the multichannel sound effect, several output terminals and sound signal cables have to be used for connection with the front, the center and the rear surround channels or the woofer. Accordingly, the AUDIO OUT terminal on the rear panel of the DVD player or the surround amplifier is connected with over six plugs and sound signal cables in order to transmit the sound signals to each of the speakers, thereby causing the cable clutter on the rear panel and, therefore, leading to much inconvenience.
5.1-ch or multichannel sound output brings the listeners an excellent enjoyment of the best sound effect. However, this will trouble the one who is at work and doesn""t listen to the sound. When putting on headphone, the listeners can""t enjoy the multichannel surround sound effect since the phone plug (a) can only reach the right and left (two) channel stereophonic effect.
Currently, the 5.1-ch headphone is commercially available. However, this kind of product only simulates the 5.1 decoding function rather than the reproduction of the 5.1-ch original sound. In addition, a negative effect will be produced when the simulated sound is not processed well.
Since the headphone is considered as attachments rather than the core of the stereo set and the profit thereof is low, only few want to invest in this field for further development. Therefore, the currently existing headphone gives only two channel original sound. The reason is that the conventional phone plug has only two or three electric poles (one of them is for earthing) so that the single plug can""t transmit multichannel sound signal.
Another conventional multipole plug (TW 294851, see Attachment 1), disclosed by a Japanese firm, is shown in FIG. 2. In order to improve the conventional multipole plug shown in FIG. 1, this multipole plug has a pin-shaped electric pole (b) and a plurality of concentric cylinders (c), thereby forming a multiple socket poles. The volume of this kind of plug is greater than the conventional phone plug (a) and this plug doesn""t fit in the common phone jacks. Accordingly, its application is much limited so that it""s not practical as a phone plug.
A further conventional multipole plug, as shown in FIGS. 3 and 4, includes a shaftlike plug (d) with a plurality of conductive poles and several conductive prongs (e) which are formed in a body by injection-molding process. However, this kind of plug is too complicate and large in volume so that it""s also not practical as a phone plug.
Since the phone plug and the phone jack had been widely used, four standard diameters (6.35 mm, 5.33 mm, 3.56 mm and 2.54 mm) thereof: was developed. The smaller diameters (3.56 mm and 2.54 mm) are mostly applicable to the Walkman or the bedside stereo sets while the greater diameters (6.35 mm, 5.33 mm) are mostly applicable to the professional stereo sets. Therefore, any plugs which deviate from the above four standard diameters can""t be accepted by the market so that such plugs don""t meet the requirement of practicalness.
Another reason why the further development of the multichannel phone plug was not valued lies in that safety standards for the phone plug and the phone jack are regulated in many countries. The phone plug and the phone jack can be loaded with up to the current and the voltage in the following table while the insulating part can""t have the flashover or any destroying phenomena.
It is still not attainable by the current technology that at least six electric poles are formed on the above plugs with four different diameters. Moreover, the insulating piece has to meet the above-mentioned requirements. Furthermore, the sound signals transmitted by each of the electric poles can""t be disturbed by one another in order to keep the sound effect.
It is a primary object of the present invention to remove the above-mentioned drawbacks and to provide a multichannel phone plug whose different diameters meet the standard regulated in every country in the world while six or seven electric poles are mounted on the surface of the single shaftlike terminal for transmitting five or six sound signals. Therefore, it is practical in use and can be widely accepted.
It is another object of the present invention to provide a multichannel phone plug which is particularly applicable to the headphones through which the multichannel sound effect produced by the DVD player or surround amplifier can be heard.
It is a further object of the present invention to provide a multichannel phone plug which can replace the conventional audio output with a plurality of terminals in order to simplify the configuration of the terminal.
It is still another object of the present invention to provide a multichannel phone plug which is applicable to the headphone for the international conference, and the user can receive multichannel sound signals at the same time.